SIP
SIP-trunking services are still are rapidly growing in availability though interoperability challenges spurred by different vendor and service provider implementations of SIP remain the key obstacle to a successful implementation. The SIP Forum’s SIPconnect initiative is a multi-vendor effort to define SIP trunking interoperability standards to enable broad support between service provider and IP-PBX platforms. Recently the SIP Forum began work on an update to SIPconnect, designed to support more features and address shortcomings of the current standard. Make sure to ask your providers (both service provider and IP-PBX) about their support for SIPconnect 1.0, and their plans to support 1.1.
